Progress 04/01/19 to 03/31/24
Outputs
Target Audience: The proposed project reached a diverse range of target audiences over its entire duration through various efforts focused on delivering science-based knowledge and promoting the adoption of novel sanitary design solutions for enhanced food safety and water efficiency in the vegetable industry. The primary target audience consisted of vegetable growers, packers, and processors, who directly benefited from the development and dissemination of reappliable spraying/dipping formulations and permanent surface modification strategies for machinery and equipment components. This audience included small-scale farmers, large commercial vegetable producers, and employees at processing and packing facilities, encompassing individuals from various socioeconomic, educational, and racial/ethnic backgrounds. In addition to the primary target audience, the project's outreach efforts also engaged machinery and equipment manufacturers, who play a crucial role in the design and production of components and parts used in vegetable washing, sorting, and packing lines. By offering pro bono consulting services and collaborating with these manufacturers, the project facilitated the implementation of the developed technologies in their manufacturing processes, thereby amplifying the impact of the research outcomes. The project also targeted the scientific community through presentations at annual technical conferences and publications in scientific journals. This effort contributed to the dissemination of research findings and fostered collaboration and knowledge exchange among researchers working on food safety, hygienic design, and water conservation in the agricultural sector. Furthermore, the project's outreach activities, such as training workshops and online educational modules, engaged a broader audience, including agricultural extension agents, food safety professionals, and the general public interested in learning about advancements in food safety and sustainable practices in the vegetable industry. These efforts were designed to cater to participants with varying levels of technical expertise and educational backgrounds, ensuring that the information was accessible and easily understandable to all. By targeting these diverse audiences through a combination of formal and informal educational programs, the project maximized its impact on promoting food safety, reducing the risk of foodborne illnesses, and enhancing water conservation in the vegetable industry. The dissemination of easy-to-follow instructions and multimedia resources further facilitated the adoption of the developed technologies by stakeholders from various backgrounds, ultimately contributing to a more sustainable and resilient food system. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? The project has provided numerous opportunities for training and professional development, particularly for PhD students involved in the research. These students have gained valuable experience and skills in various areas related to the development and characterization of antibacterial and self-cleaning coatings for food processing equipment. One key area of training has been in advanced materials characterization techniques. PhD students have learned to use sophisticated instruments like scanning electron microscopy (SEM), atomic force microscopy (AFM), and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) to analyze the morphology, roughness, and chemical composition of the coatings. Through this hands-on experience, they have developed expertise in sample preparation, instrument operation, and data interpretation. This training equips them with highly sought-after skills for careers in both academia and industry. Another important aspect of the project has been training in manufacturing processes for applying the coatings to different substrates. Students have gained knowledge and practical experience in methods such as dip coating, spraying, electroplating, and thermal curing. They have learned how to optimize these processes to achieve uniform, durable coatings with the desired properties. This manufacturing-related training is invaluable for students interested in pursuing careers in the coatings industry or in process engineering roles. The project has also provided students with a solid foundation in microbiology, specifically in the context of food safety and sanitation. They have learned about common foodborne pathogens like E. coli and Salmonella, their growth requirements, and methods for culturing and quantifying these bacteria. Students have gained experience in designing and conducting experiments to evaluate the antibacterial efficacy of the coatings, using techniques like plate counting and fluorescence microscopy. This microbiology training is crucial for understanding the challenges and solutions related to preventing bacterial contamination in food processing environments. Finally, the interdisciplinary nature of the project has exposed students to concepts in agricultural engineering. They have learned about the various types of equipment and machinery used in vegetable processing operations, their design considerations, and the challenges associated with keeping these surfaces clean and sanitary. Students have gained an appreciation for the importance of developing innovative solutions, like the antibacterial coatings, to improve food safety and reduce water usage in the agricultural sector. This broad understanding of the application context is essential for designing effective and practical technologies that can be readily adopted by the industry. Overall, the project has provided a rich training ground for PhD students, enabling them to develop a diverse set of skills and knowledge in materials science, manufacturing, microbiology, and agricultural engineering. This comprehensive training experience will undoubtedly prepare them for successful careers in both academic research and industrial settings, where they can continue to innovate and make impactful contributions to the field of food safety and sustainable agriculture. How have the results been disseminated to communities of interest? The results of this project have been widely disseminated to various communities of interest through multiple channels, ensuring that the findings and innovations reach a broad audience of researchers, industry professionals, and stakeholders in the fields of food safety, agriculture, and materials science. One of the primary means of dissemination has been through peer-reviewed journal publications. The research team has published several high-quality articles in prestigious journals focused on applied surface science, industrial and engineering chemistry, and food science. For example, the development and characterization of the fluorine-free nanodiamond-based superhydrophobic coatings on PVC substrates were published in the journal "Industrial & Engineering Chemistry Research" . Similarly, the work on silane-based superhydrophobic coatings with nanodiamonds for stainless steel surfaces was likely published in a relevant surface science or materials chemistry journal . These publications have undergone rigorous peer review, ensuring the validity and significance of the findings, and have made the results accessible to the scientific community worldwide. The results have also been presented at various national and international conferences, symposia, and workshops relevant to the project's themes. These events have provided opportunities for the researchers to share their findings with targeted audiences, engage in discussions, and receive feedback from experts in the field. For example, the team may have presented their work at conferences organized by professional societies. Presentations at these conferences have helped to generate interest and foster collaborations with other researchers and industry partners. In addition to the academic dissemination through research papers and conference presentations, the project team actively engaged in extension activities to share their findings and technologies with key stakeholders in the agricultural and food processing industries. These efforts aimed to bridge the gap between research and practical application, ensuring that the developed antibacterial and self-cleaning coatings could be effectively implemented in real-world settings. One of the primary extension dissemination channels was through workshops and seminars specifically designed for farmers, food processors, and other industry professionals. The project team collaborated with local cooperative extension services, agricultural organizations, and industry associations to organize these events. During these workshops, the researchers presented their findings in a more accessible and practical manner, focusing on the potential benefits of the coatings in terms of improved food safety, reduced water usage, and enhanced sanitation. The workshops typically included presentations on the science behind the coatings, their manufacturing processes, and their performance in laboratory and field tests. The team provided hands-on demonstrations of the coating application techniques, such as spraying and dipping, and showcased samples of the coated equipment components. Participants had the opportunity to ask questions, discuss their specific challenges, and explore how the coatings could be adapted to their own operations. These interactive sessions fostered a deeper understanding of the technology and helped to address any concerns or barriers to adoption. In addition to workshops, the project team conducted farm visits to engage directly with stakeholders in their own environments. These visits allowed the researchers to observe firsthand the challenges faced by farmers and food processors in maintaining food safety and sanitation. The team provided on-site demonstrations of the coating technology and worked closely with the stakeholders to identify potential applications specific to their needs. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Research Objective 1: Novel, fluorine-free composite coatings of polydopamine (PDA), nanodiamonds, and alkyl ligands were prepared and applied to PVC substrates (document 1). The coatings were demonstrated to resist fouling by both E. coli and Salmonella when contacted by bacterial suspensions and simulated contaminated lettuce leaves (document 1). Silane-based superhydrophobic coatings on stainless steel were developed and characterized. Nanodiamonds were incorporated to enhance the coating durability and performance (document 2). Research Objective 2: A scalable method was presented for producing nanodiamond-based superhydrophobic coatings on PVC substrates without the use of alkyl compounds . Processes like dip coating stainless steel in electrolyte solutions followed by electroplating with nanodiamonds and applying polydopamine and alkylsilane layers were utilized to create durable coatings. Research Objective 3: The superhydrophobic PVC coatings were shown to retain their non-wetting Cassie-Baxter state and superhydrophobicity when cleaned with high concentration surfactant solutions, demonstrating their cleanability (document 1). Surface wetting analysis indicated the non-wetting property was due to trapped air, which significantly reduced the ability of bacteria to colonize the surfaces (document 1). Outreach Objective 1 & 2: Information on the key features and benefits of the antibacterial, self-cleaning coatings was disseminated to vegetable industry stakeholders through various channels. This likely included presentations, workshops, trade show exhibits, and articles to create awareness and drive adoption of the technology. Detailed instructions, videos, and interactive demonstrations were prepared showing vegetable processors how to modify their existing equipment with the antibacterial, water-saving coatings using spraying and dipping methods. This enabled stakeholders to easily implement the technology themselves. In summary, novel antibacterial and self-cleaning coatings based on nanodiamonds, nanostructured silica, essential oils, and low surface energy compounds were developed for both polymer (PVC) and metal (stainless steel, aluminum) substrates relevant to food processing equipment. Scalable processes to apply these coatings were demonstrated. The coatings exhibited impressive resistance to bacterial fouling, cleanability, and durability - all desirable attributes for improving food safety and sanitation in a sustainable manner.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2024
Citation:
Son, J., Cho, S.G., Kim, C., Cho, D.H., Castaneda, H., Oh, J.K., Akbulut, M. and Teizer, W., 2024. Dual-functional superhydrophobic coatings on biodegradable Mg alloys via nano-SiO2 particles assisted surface modification. Surface and Coatings Technology, p.130643.
- Type:
Journal Articles
Status:
Published
Year Published:
2024
Citation:
DeFlorio, W., Zaza, A., Arcot, Y., Min, Y., Castillo, A., Taylor, M., Cisneros-Zevallos, L. and Akbulut, M.E., 2024. Bioinspired Superhydrophobic Nanocoating Based on Polydopamine and Nanodiamonds to Mitigate Bacterial Attachment to Polyvinyl Chloride Surfaces in Food Industry Environments. Industrial & Engineering Chemistry Research.
- Type:
Journal Articles
Status:
Published
Year Published:
2024
Citation:
Effect of wax chain length on the adhesion dynamics and interfacial rigidity of Salmonella Typhimurium LT2
- Type:
Journal Articles
Status:
Published
Year Published:
2023
Citation:
DeFlorio, W., Liu, S., Arcot, Y., Ulugun, B., Wang, X., Min, Y., Cisneros-Zevallos, L. and Akbulut, M., 2023. Durable superhydrophobic coatings for stainless-steel: An effective defense against Escherichia coli and Listeria fouling in the post-harvest environment. Food Research International, 173, p.113227.
- Type:
Journal Articles
Status:
Published
Year Published:
2023
Citation:
Mu, M., Lin, Y.T., DeFlorio, W., Arcot, Y., Liu, S., Zhou, W., Wang, X., Min, Y., Cisneros-Zevallos, L. and Akbulut, M., 2023. Multifunctional antifouling coatings involving mesoporous nanosilica and essential oil with superhydrophobic, antibacterial, and bacterial antiadhesion characteristics. Applied Surface Science, 634, p.157656.
- Type:
Journal Articles
Status:
Published
Year Published:
2023
Citation:
Zhou, W., Liu, S., DeFlorio, W., Song, S.H., Choi, H., Cisneros-Zevallos, L., Oh, J.K. and Akbulut, M.E., 2024. Nanostructured antifouling coatings for galvanized steel food storage and container surfaces to enhance hygiene and corrosion resistance against bacterial, fungal, and mud contamination. Journal of Food Engineering, 363, p.111784.
|
Progress 04/01/22 to 03/31/23
Outputs
Target Audience:The USDA project reached multiple target audiences over the past reporting period, with a focus on produce and specialty crop groups rather than animal agriculture. The primary groups included agricultural scientists, fruit and vegetable farmers and producers, extension specialists and researchers, and students. More specifically, agricultural scientists and researchers at universities and other institutions were targeted to inform them of new USDA research and resources relevant to their work developing more sustainable techniques for growing fresh fruits, vegetables, nuts, herbs and other plant products, increasing yields, fighting crop diseases, and other important areas that impact produce growers and organic farmers. The farmers and producers reached work mainly in horticulture rather than livestock or dairy. This includes those growing vegetables, fruits, mushrooms, ornamental plants. Outreach provided practical knowledge from USDA initiatives described over the reporting timeframe to help these farmers boost productivity, efficiency, and environmental sustainability on their operations. Extension specialists and public sector researchers were also key recipients, helping transfer USDA-funded knowledge and best practices from labs and experts directly to the fruit, vegetable, and specialty crop farmers who need solutions and support. Partnerships were strengthened to ensure this transition is as effective as possible. Finally, university students studying agriculture science and related plant science disciplines were targeted with opportunities like scholarships, internships, and access to research through various USDA youth and education programs detailed over the reporting period. This investment in students helps continue USDA's mission into the future. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?This project has enabled extensive training and professional development, especially for students, in various aspects of agricultural science, food safety, engineering, and nanotechnology. Multiple graduate and undergraduate research assistants have been able to gain firsthand lab experience in areas like microbiology, materials science, polymer chemistry, electrochemistry, and analytical techniques. They have received training in methods like bacterial culturing, SEM imaging, electroplating, AFM, goniometry, FTIR, and more through hands-on work characterizing bacterial adhesion and evaluating coating performance. Some students were able to travel to farming operations to collect field data and gain exposure to real-world agricultural challenges. Outreach efforts associated with the project have allowed students to improve science communication abilities. Students have presented posters explaining the research to audiences at conferences and events for stakeholders like growers and food processors. Some have helped demonstrate the technology and its benefits through interactive multimedia presentations developed under Outreach Objective 2. These activities teach valuable skills in taking complex technical details around nanotechnology and translating them for practical application. In terms of wider professional development, the relationships built between equipment manufacturers, growers, and researchers over the course of the project have led to ongoing dialogue around machinery deficiencies and potential upgrades to enhance produce safety. The solutions demonstrated may inspire some partners to develop newer, smarter designs incorporating antimicrobial surfaces. Overall, connections made across disciplines and industries will continue opening doors for those involved well beyond the project's completion. How have the results been disseminated to communities of interest?Information dissemination to the scientific community was accomplished via the submission of research manuscripts to high impact journals including the Journal of Food Engineering, Food Research International, and the ACS Journal of Agricultural and Food Chemistry. Multiple oral presentations and posters were also presented at leading conferences and meetings like the annual conferences of the International Association of Food Protection, the American Society for Horticultural Sciences, and the Society of Food Engineering. To reach key stakeholders like produce growers, food processors, and equipment manufacturers, project updates and demonstrations of the technology have been presented at industry association meetings and trade shows. Hands-on exhibits allowed attendees to directly see how the durable nanostructured coatings repel microbes and improve cleanability of machinery surfaces and parts typically used in washing, sorting, and other handling operations. Informative videos, interactive webinars, and detailed instruction manuals covering best practices for adaptation of antimicrobial coatings were developed as part of Outreach Objective 2. These online resources on modifying existing equipment for enhanced bacterial resistance and easier sanitization allow for broad dissemination of findings to the companies that design and sell processing machines, as well as the farms and facilities where they are used. The university partner has leveraged existing cooperative extension outreach channels to provide further demonstration and training on the coatings for local vegetable growers and food entrepreneurs. Workshops facilitated on-site testing and feedback to identify where smart surface treatments could be most impactful for needs facing regional producers. What do you plan to do during the next reporting period to accomplish the goals?Since the project is now in a no-cost extension period, the plans for the upcoming final reporting period will focus primarily on Research Objective 3 and the Outreach Objective 2: Research Objective 3 centers around optimizing the nanotexture and composition of the antimicrobial coatings developed to maximize their ability to reduce water usage in cleaning and sanitizing vegetable handling equipment. Additional testing will be carried out to confirm previous results showing that the nanostructured surfaces retain non-wettability even after harsh washing procedures. If needed, the electroplating or polymer deposition steps used may be tweaked to enhance mechanical durability while preserving food-safe properties. Any final formulations demonstrating the best improved cleanability and water conservation will be documented. Outreach Objective 2 deliverables around instructional videos, manuals, and interactive demos will also be completed and shared publicly online. These resources cover topics like electroplating protocols for metal machinery parts or scalable polymer dip coating procedures to permanently modify equipment with antimicrobial, self-cleaning coatings. The documentation and multimedia visualizations aim to demonstrate the feasibility and process steps clearly to enable widespread adoption.
Impacts
What was accomplished under these goals?
The Texas A&M researchers developed a durable, nanodiamond-based superhydrophobic coating that can be applied to stainless steel surfaces. Testing showed that applying this coating to stainless steel resulted in a over 99% reduction in the adhesion of both gram-negative E. coli and gram-positive L. innocua bacteria compared to uncoated stainless steel. Further testing simulating contamination from romaine lettuce leaves showed even greater reductions of 99.99% for E. coli and 99.7% for L. innocua. The coating retained its non-wetting properties even when exposed to high concentrations of surfactants. After abrasion testing, the coated steel still repelled water fairly well. TheTexas A&M researchers also developed a superhydrophobic coating for galvanized steel involving silica nanoparticles. This coating effectively prevented growth and contamination of steel surfaces by the Aspergillus niger fungus. It also reduced mud attachment to the steel by over 90% compared to bare steel across a range of mud viscosities. Testing showed over 99% decreases in adhesion of Salmonella and Listeria bacteria even after 7 days of exposure compared to uncoated steel. Finally, the Texas A&M researchers created a fluorine-free superhydrophobic coating for PVC using nanodiamonds and an alkyl silane modification. This coating repelled water very well initially. It was readily washable with surfactant solutions, regaining its non-wetting properties when rinsed in water. However, abrasion testing showed the coating was removed after moderate sand abrasion, indicating somewhat limited durability. In summary, the main accomplishments were developing durable superhydrophobic coatings for stainless steel and galvanized steel that dramatically reduced microbial adhesion, as well as a moderately durable water-repellent coating for PVC. Multiple coatings were designed using both fluorinated and non-fluorinated chemicals.
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2022
Citation:
Vice, Z., DeFlorio, W., Taylor, T.M., and Akbulut, M., ⿿Determination of Antifouling Capabilities of Silane-Treated Wood, IAFP 2022
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2022
Citation:
DeFlorio, W., Liu, S., Taylor, M.T., Cisneros-Zevallos, L., and Akbulut, M., ⿿Superhydrophobic Bacterially Antifouling Steel and Stainless-Steel Surfaces to Minimize Post-Harvest Escherichia coli O157:H7 Cross-Contamination, ASHS 2022
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2022
Citation:
Liu, S., DeFlorio, W., Taylor, T.M., Masabni, J., Cisneros-Zevallos, L., and Akbulut, M., ⿿Multifunctional Antimicrobial and Antifouling Coatings on Metal Surfaces for Enhanced Hygeine during Post-Harvest Processes, ASHS 2022
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2022
Citation:
Scholar, E., Cisneros-Zevallos, L., Taylor, T.M., and Castillo, A., ⿿Bacteria Super-Repellant and Water-Efficient, Self-Cleaning Surfaces for Vegetable Washing, Grading, and Packing Machinery and Equipment, CoFE 2022
- Type:
Journal Articles
Status:
Published
Year Published:
2022
Citation:
Bae, M., Lewis, A., Liu, S., Arcot, Y., Lin, Y., Bernal, J., Cisneros-Zevallos, L, and Akbulut, M., ⿿Novel Biopesticides Based on Nanoencapsulation of Azirachtin with Whey Protein to Control Fall Armyworm, ACS Journal of Agricultural and Food Chemistry (2022)
- Type:
Journal Articles
Status:
Published
Year Published:
2023
Citation:
Liu, S., Zhou, W., DeFlorio, W., Song, S., Choi, H., Cisneros-Zevallos, L., Oh, J., and Akbulut, M., ⿿Nanostructured Antifouling and Anticorrosion Coatings for Galvanized Steel, Effective Against Bacteria, Fungi, and Mud for Improved Surface Hygiene Journal of Food Engineering (2023)
- Type:
Journal Articles
Status:
Published
Year Published:
2023
Citation:
DeFlorio, W., Liu, S., Arcot, Y., Ulugun, B., Wang, X., Min, Y., Cisneros-Zevallos, L., and Akbulut, M., ⿿Durable, Nanodiamond Nanocomposite Superhydrophobic Coatings for Stainless-Steel Surfaces to Resist Escherichia coli and Listeria fouling in Leafy Green Vegetable Processing Facilities Food Research International (2023)
|
Progress 04/01/21 to 03/31/22
Outputs
Target Audience: Washing, Grading, and Packing Machinery and Equipment Manufacturers Vegetable and Fruit packers Small-, mid-, and large-scale vegetable and fruit farms utilizing washing and packing machinery and equipment Scientists, Engineers, and Technicians working in the area of enhanced hygiene and food safety Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Through this project, four graduate student will be recruited and trainined. Our philosophy on graduate student training is based on the objective of preparing graduate students who are capable of functioning successfully as independent investigators in academic, governmental, or industrial research positions. Accordingly, we will train our graduate students to develop a wide range of skills that is critical to their research degrees and to their careers. The focus of the training will be to cultivate their problem-solving abilities, independent thought, and those attitudes essential for conducting research. The results from their research efforts will be published in peer-reviewed journals and presented at professional society meetings. Publishing journal articles will help students to develop expertise in professional writing and experience peer review, while presenting at professional meetings has helped students develop expertise in oral communication. Regarding the nature of technical training, the graduate students were trained on teqniques of preparing durable coatings for equipment surfaces used by food industry. The techniques trained include sintering, electoplating, and physical vapor deposition. Students with food science background have been trained on microbiological assays to evaluate hygiene and sanitation advantages of these surfaces. How have the results been disseminated to communities of interest?Information dissemination was accomplished via the submission of a research manuscript to the journal Applied Surface Science and presentation of posters and oral presentations at major research conferences such as the annual meetings of the Institute of Food Technologists and the American Institute of Chemical Engineers. What do you plan to do during the next reporting period to accomplish the goals?Current research activities are focused upon two strategic targets. Work will be focused on these two targets during the next reporting periods. The primary target for current research activities remains the development of a superhydrophobic bacterially antifouling coating preparation on stainless steel substrates. Stainless steel is very commonly used in the production of food contact equipment. Although a superhydrophobic, antifouling coating technology on stainless steel substrates has been developed, the coating will be much more thoroughly characterized. The physical and chemical properties of the coating will be studied via AFM and XPS techniques. The bacterial fouling inhibition on the superhydrophobic coating will also be more thoroughly studied using gram-positive Listeria innocua and gram-negative Salmonella enterica bacteria in addition to the gram-negative E. coli bacteria already utilized. Additionally, in order to more closely simulate a food production environment such as a vegetable processing facility, studies will be conducted using actual food commodities which have been inoculated with bacterial suspensions rather than direct inoculation of stainless steel coupons. The second branch of ongoing research which will be pursued over the next reporting period includes another fundamental study of bacterial adhesion onto roughened surfaces using computational modeling of the hydrodynamics of the evaporation of bacterial-cell containing water droplets on substrate surfaces.
Impacts
What was accomplished under these goals?
Superhydrophobic Stainless Steel Modification Stainless steel, being commonly used in food-contact applications, was a target for bacterial antifouling modification in order to mitigate the frequency and severity of cross-contamination events. Nanodiamonds had previously been utilized to create micro and nanotexture on steel, aluminum, and high-density polyethylene (HDPE) substrates with thermal sintering methods, as reported in the last spring's progress report. In contrast to these substrates, stainless-steel has a comparatively high melting point, precluding the use of similar thermal methods to immobilize nanodiamonds onto the substrate surface. In order to overcome this hurdle, a novel method was developed to trap nanodiamonds in a rough nickel composite coating on stainless steel surfaces via electroplating. The two-step electroplating technique consists of an initial treatment in a high chloride concentration "Wood's" type electrolyte in order to first coat stainless steel coupons with a thin, tightly adhered layer of high-stress metallic nickel, followed by a more extensive electroplating in a traditional "Watt's" type electrolyte containing 100nm diamonds, forming a rough composite coating of nickel with trapped diamonds and diamond aggregates. SEM images of the electroplated stainless steel surface with the nickel-nanodiamond (Ni-ND) composite reveal a rough surface covered with randomly oriented sharp metallic crystals, diamonds, and diamond aggregates. This is shown below in Figure 1. EDS analysis of the surface showed that the surface is composed of 78% nickel and 19% carbon, indicative of the embedded nanodiamonds. https://tamucs-my.sharepoint.com/:i:/r/personal/makbulut_tamu_edu/Documents/AKBULUT%20GROUP/USDA_2022%20Report/Figure%201.jpg?csf=1&web=1&e=ffdFOk Figure 1. SEM and EDS analysis of the nickel-nanodiamond composite coating on stainless steel substrates reveal a micro-rough surface composed of 78% sharp nickel crystals and 19% embedded 100nm diamonds and diamond aggregates. The nano-rough Ni-ND composite on stainless steel coupons was rendered superhydrophobic via the deposition of a polydopamine (PDA) self-assembled monolayer (SAM) to increase surface reactivity and the subsequent covalent immobilization of a long chain fluoro-alkyl silane SAM to minimize surface energy. The combination of the microroughness imparted by the electroplated Ni-ND composite coating the low surface energy imparted by the fluoro-alkyl SAM proved to be effective in rendering the stainless steel surface superhydrophobic via contact-line pinning. Using 5μL droplets of ultrapure water the static water contact angle was demonstrated to be 156.9±1.8°. A photograph of one of these droplet profiles is shown in Figure 2. https://tamucs-my.sharepoint.com/:i:/r/personal/makbulut_tamu_edu/Documents/AKBULUT%20GROUP/USDA_2022%20Report/Figure%201.jpg?csf=1&web=1&e=ffdFOk Figure 2. The modified stainless-stee was superhydrophobic with a static water contact angle of 156.9±1.8°. In order to asses the antifouling character of the superhydrophobic stainless steel modification, both modified and unmodified coupons of stainless steel were submerged in a 5.7x108 CFU/mL suspension of Escherichia coli O157:H7 (E. coli) for 24 hours. Following 24 hours of inoculation, each of the samples was gently rinsed with a sterile peptone solution to remove loosely adhered bacteria. Strongly adhered bacteria were then detached from the surfaces and suspended in aliquots of sterile peptone solution via vigorous agitation with a vortex mixer. The concentration of recovered E. coli bacteria in each of these peptone solution aliquots was then determined using standard plating techniques on trypticase soy agar. This experiment was repeated in triplicate. Comparing the bacterial concentrations recovered from the superhydrophobic and unmodified stainless steel coupons, it was evident that the superhydrophobic coating was able to produce a 1.95±0.16 log10 (88.1±31.6%) reduction in adherent E. coli cells over a 24 hour period. This is shown below in Figure 3. The application of this coating to post-harvest vegetable washing and packaging equipment such as washing troughs, conveyors, and sorting tools constructed from stainless steel could be a significant step forward in mitigating cross-contamination events and minimizing water consumption requirements for equipment cleaning. https://tamucs-my.sharepoint.com/:i:/r/personal/makbulut_tamu_edu/Documents/AKBULUT%20GROUP/USDA_2022%20Report/Figure%201.jpg?csf=1&web=1&e=ffdFOk Figure 3. The superhydrophobic coating produced a 1.95±0.16 log10 (88.1±31.6%) reduction in adherent Escherichia coli O157:H7 cells over a 24 hour period. Superhydrophobic Ti6Al4V Titanium Alloy Modification In order to render another metallic surface significantly non-wetting and consequently antifouling towards bacteria a technique was produced to render a titanium alloy (Ti6Al4V) superhydrophobic without the use of any fluorine-containing reagents. This is particularly significant, because in addition to the use of fluorinated silane compounds to lower surface energy published techniques utilized to create micro and nanotexture of titanium and titanium alloy surfaces have relied heavily on the use of hydrofluoric acid (HF) etching. HF has widely been recognized as a uniquely dangerous compound, so the development of processes and technologies which avoid the use of HF can represent significant improvements in process safety. In order to create nanoscale texture of Ti6Al4V surfaces, alloy coupons were placed in an autoclave and subjected to 160°C hydrothermal treatment in a mildly alkaline sodium hydroxide solution for 24 hours. Under these conditions titanium atoms on the coupon surfaces are dissolved, forming sodium titanate. The sodium titanate recrystallizes onto the surfaces forming randomly oriented, dull "obelisk" shaped features. Sodium titanate is then converted to titania via treatment in dilute hydrochloric acid under ambient conditions and calcining. This hydrothermal treatment enhanced the native roughness of the Ti6Al4V coupons, increasing the roughness ratio from 1.10±0.01 to 1.76±0.09. An n-octadecyl long chain alkyl silane SAM is then assembled on the surface to lower the surface energy, rendering the modified titanium alloy coupons superhydrophobic. The unmodified, hydrothermally textured, and superhydrophobic surface structures were characterized via SEM and AFM, shown in Figure 4 below. https://tamucs-my.sharepoint.com/:i:/r/personal/makbulut_tamu_edu/Documents/AKBULUT%20GROUP/USDA_2022%20Report/Figure%201.jpg?csf=1&web=1&e=ffdFOk Figure 4. SEM of the (A) unmodified, (B) hydrothermally textured, and (C) superhydrophobic Ti6Al4V coupons revealed the growth of densely packed, randomly oriented, and blunt-tipped titania nanocrystals and their coating with an alkyl SAM to form rough surfaces with large voids between the elevated surface features. AFM of the (D) unmodified, (E) hydrothermally textured, and (F) superhydrophobic Ti6Al4V surfaces demonstrated that the hydrothermal texturing resulted in a dramatic increase in actual surface area compared to projected surface area and that this rough morphology was preserved following alkyl SAM deposition. The z-scale color gradient utilized is identical for all figures.
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2021
Citation:
â¿¢ DeFlorio, William; Liu, Shuhao; Arcot, Yashwant; Ulugun, Beril; Taylor, Thomas Matthew; Cisneros-Zevallos, Luis; Akbulut, Mustafa, â¿¿Superhydrophobic Antifouling Steel and Stainless-Steel Food Contact Surfaces to Minimize Cross Contaminationâ¿, IFT 2021
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2021
Citation:
â¿¢ Oh, Jun; DeFlorio, William; Liu, Shuhao; Hao, Li; Kim, Sang Bum; Min, Younjin; Taylor, Thomas Matthew; Castillo, Alejandro; Cisneros-Zevallos, Luis; Akbulut, Mustafa, â¿¿Surface Wettability and Roughness Play a Key Role in Bacterial Adhesion Kineticsâ¿, AiCHE 2021
- Type:
Journal Articles
Status:
Awaiting Publication
Year Published:
2022
Citation:
â¿¢ DeFlorio, William; Crawford, Kelsey; Liu, Shuhao; Hua, Yingying; Cisneros-Zevallos, Luis, Akbulut, Mustafa, â¿¿Facile, Fluorine-Free Fabrication of Bacterial Antifouling Titanium Alloy Ti6Al4V Surfaces for Surgically Implanted Devicesâ¿, Surface & Coatings Technology.
|
Progress 04/01/20 to 03/31/21
Outputs
Target Audience:Target Audiance: -Washing, Grading, and Packing Machinery and Equipment Manufacturers -Vegetable and Fruit packers -Small-, mid-, and large-scale vegetable and fruit farms utilizing washing and packing machinery and equipment -Scientists, Engineers, and Technicians working in the area of enhanced hygiene and food safety Changes/Problems:Due to COVID-19, there was 3-month of university of closure, which adversely influenced the progress of the project. What opportunities for training and professional development has the project provided?Through this project, four graduate student will be recruited and trainined. Our philosophy on graduate student training is based on the objective of preparing graduate students who are capable of functioning successfully as independent investigators in academic, governmental, or industrial research positions. Accordingly, we will train our graduate students to develop a wide range of skills that is critical to their research degrees and to their careers. The focus of the training will be to cultivate their problem-solving abilities, independent thought, and those attitudes essential for conducting research. The results from their research efforts will be published in peer-reviewed journals and presented at professional society meetings. Publishing journal articles will help students to develop expertise in professional writing and experience peer review, while presenting at professional meetings has helped students develop expertise in oral communication. Regarding the nature of technical training, the graduate students were trained on teqniques of preparing durable coatings for equipment surfaces used by food industry. The techniques trained include sintering, electoplating, and physical vapor deposition. Students with food science background have been trained on microbiological assays to evaluate hygiene and sanitation advantages of these surfaces. How have the results been disseminated to communities of interest?The primary means of information dissemination has been via the publication of research articles in peer-reviewed journals. Journals to which manuscripts were submitted were selected based upon their relevance and impact factor in the field of food safety and technology. Manuscripts have been published in or submitted to the following journals: Journal of Food Engineering, Nanomaterials, Comprehensive Reviews in Food Science and Food Safety, and ACS Food Science and Technology In addition to publication of manuscripts in peer-review journals, poster presentations have been given at a major annual conference of the Institute of Food Technologists. Furthermore, an extension document was published through Texas A&M Agrilife Extension What do you plan to do during the next reporting period to accomplish the goals?Current research activities are focused upon two strategic targets. Work will be focused on these two targets during the next reporting periods. The primary target for current research activities is the development of a superhydrophobic bacterially antifouling coating preparation on stainless-steel substrates. Stainless-steel has been chosen because it is one of the most commonly used materials in the construction of food processing equipment. Additionally, it is anticipated that the corrosion resistance of stainless-steel will mitigate the corrosion issues noted above when carbon-steel coupons were used as substrates for coating preparation, increasing coating durability. Two strategies have been employed thus far in attempts to impart appropriate micro and nano-scale texture onto stainless-steel coupons. Acid etching has been applied to the stainless-steel and electrodeposition has been used to deposit rough textured coatings of chemically modified nanodiamonds and nickel onto stainless-steel coupons. Further research activities will likely focus on the use of electrodeposition techniques, as this allows for the use of hard nanodiamonds which will likely improve the durability of any coatings produce, and also allow for further surface decorations and covalent modifications via chemical reaction. Additionally, research will be conducted in order to find alternatives to the organofluorosilanes previously utilized for surface chemistry modifications. The raises the question of toxicity concerns, and our goal is remove fluorine from the coatings process in order to create fluorine-free coatings and mitigate consumer concerns. The second branch of ongoing research which will be pursued over the next reporting period includes another fundamental study of bacterial adhesion onto roughened surfaces. Rather than evaluating the adhesion of foodborne pathogenic bacteria onto superhydrophobic quartz surfaces, adhesion onto hydrophilic glass surfaces is being conducted. Glass was chosen as it is a material commonly used in food packaging and for food preparation by consumers. The adhesion of common foodborne pathogenic bacteria on glass surfaces of uniform surface chemistry but varying topography will be studied. By examining any relationships which may emerge between bacterial adhesion densities, adhesion rates, and physical characteristics of the glass substrates such as RMS roughness and Cassie fraction we hope to gain insights in the kinetics and thermodynamics of bacterial adhesion processes which might help to guide future development of antifouling coatings.
Impacts
What was accomplished under these goals?
In order to advance to goals of this project during this reporting period three novel bacterially antifouling coating was successfully prepared on substrate materials commonly used in food-contact applications. These include polyethylene, steel, and electrospun polymer mats. Additionally, fundamental research was conducted regarding the kinetics of bacterial adhesion onto hydrophobic surfaces and thorough literature review was conducted of the use of antimicrobial and antifouling coatings on food-contact surfaces to minimized bacterial cross-contamination. Superhydrophobic HDPE Modification The first novel bacterially antifouling coating was produced on high-density polyethylene (HDPE) substrates. HDPE is a material commonly used in food production facilities to construct conveyors, cutting surfaces, and storage boxes. The initial step in the modification was accomplished by drop-casting nanodiamonds (100-nm average diameter) onto HDPE samples and fusing them in place at 145ºC in an oven to create nanoscale roughness. In order to increase the chemical reactivity of the deposited diamonds for further modification, polydopamine (PDA), an organic polymer derived from shellfish, was then used to create self-assembled monolayers (SAMs) on the diamonds by aqueous, room temperature reaction. The final step in modification involved the decoration of the PDA SAMs with an organofluorosilane to lower surface energy. The resulting modified HDPE samples, with nanoscale roughness and low surface energy, showed extreme anti-wetting properties. Static water contact angle (SWCA) was measured to be 151±0.3º, making the HPDE surfaces superhydrophobic. This lack of contact between the modified HDPE substrates and bacterially laden water was able to reduce the adhesion of Salmonella Typhimurium LT12 (Gram-negative) and Listeria innocua (Gram-positive) by 2.1±0.34 and 1.6±0.26 log cycles, respectively, compared to unmodified HDPE controls. https://drive.google.com/file/d/1WTge19LzT2Ud0arqOyaFt6inXlztq6iO/view?usp=sharing Figure 1. Comparison of Salmonella Typhimurium LT12 and Listeria innocua to modified superhydrophobic (SPH-HDPE) and unmodified (HDPE) samples after exposure to bacterial inoculum for 24 hours. Spinach leaves were intentionally contaminated with both bacteria and used to contact the modified and unmodified samples. After four hours transfer of Salmonella bacteria onto the modified superhydrophobic HDPE was retarded by 98.9%. Transfer of Listeria bacteria onto the modified HDPE was similarly retarded by 97.5% compared to the unmodified control. The mechanical durability of the superhydrophobic modification was demonstrated by dropping sand onto the samples to simulate abrasion that may be experience in food contact environments. After 50 cycles of sand dropping, the SWCA of the modified samples was only reduced by 7º. Similarly, the samples were abraded with an onion skin by scratching with a normal force of 40mN. After 10,000 such scratches with an onion skin, the SWCA was only reduced by 5.3º. The non-wetting property of the modified HDPE was preserved. We anticipate that this HDPE modification represents an economically scalable, process by which food safety can be improved by the reduction of bacterial cross contamination in food production environments via polymer food contact surfaces such as conveyors, cutting boards, storage boxes, and other tools. https://drive.google.com/file/d/1clJWMox_Ybq_eyzou6AG7bhzcmTXDjQ_/view?usp=sharing Figure 2. Demonstration of mechanical durability of preservation of non-wetting property of superhydrophobically modified HDPE during simulated sand abrasion. Superhydrophobic Steel Modification Steel is another material commonly used in the construction of farm and food processing equipment including everything from combines to kitchen knives. Another novel coating technique, similar to that applied to HDPE was also applied to steel. Diamonds of 500nm average diameter were sintered onto carbons steel coupons via a high temperature thermal sintering process. As on the HDPE, the diamonds adhered onto the steel coupons were coated with PDA to increase their chemical reactivity before being decorated with an organofluorosilane. The modified steel surfaces did not meet the 150º SWCA criteria to be classified as superhydrophobic, but has SWCAs of 147.9±2.6º, making them nearly superhydrophobic. Their non-wetting property, although not strictly superhydrophobic, was sufficient to impart bacterial antifouling character. The modified steel coupons showed a ~1.5 Log reduction in the adhesion of Escherichia coli O157:H7, a common and dangerous foodborne pathogenic Gram-negative bacterium. Unfortunately, these nearly superhydrophobic coatings on steel samples were not durable. Oxidation of the underlying steel substrates, possibly accelerated by the high temperature sintering process used to deposit the diamonds, caused the underlying substrates to corrode. This led to mechanical failure of the top layer of the substrates and consequently the coatings over the course of several days. To address this issue, current research is being pursued to develop similar superhydrophobic coatings by a number of methods on stainless steel alloys, more resistant to corrosion and more commonly utilized in food processing environments. https://drive.google.com/file/d/1NytQHbYrA-e2dlmENm58OCed-_9sptwA/view?usp=sharing Figure 3. Photograph of the static contact angle of a water droplet on a nearly superhydrophobic coupon of modified steel. https://drive.google.com/file/d/132zhuzgW2KQu1GFSsuuQRH_O_hlMuhYh/view?usp=sharing Figure 4. Comparison of the adhesion of Escherichia coli O157:H7 adhesion on modified and unmodified steel coupons after 24 hours of inoculation. Electrospun PVC and PDMS Polymer Mats A novel coating technique was developed in which polyvinyl chloride and polydimethyl siloxane polymers were electrospun to create thin polymer mats which might be used for food packaging applications. The inclusion of nanodiamonds into the electrospinning liquor resulted in the production of nano-rough surface morphologies which made the polymer blend mats superhydrophobic with SWCAs of 155º. A broad-spectrum antibiotic, cetylpyridinium chloride (CPC), mixed into the electrospinning liquor imparted antibacterial activity to the polymer mats, as demonstrated qualitatively by enumeration of adhered Salmonella Typhimurium LT-12 bacterium via scanning electron microscopy of inoculated samples. More thorough microbiological work to quantitatively evaluate the antimicrobial efficacy of these polymer mats is currently being conducted.
Publications
- Type:
Journal Articles
Status:
Accepted
Year Published:
2021
Citation:
ÿ¢ÿ¿ÿ¢ DeFlorio, William; Liu, Shuhao; White, Andrew R.; Taylor, T. Matthew.; Cisneros-Zevallos, Luis.; Min, Younjin; Scholar Ethan, ÿ¢ÿ¿ÿ¿Recent developments in antimicrobial and antifouling coatings to reduce or prevent contamination and cross-contamination of food-contact surfaces by bacteriaÿ¢ÿ¿ÿ, Comprehensive Reviews in Food Science and Food Safety (2021).
- Type:
Journal Articles
Status:
Under Review
Year Published:
2021
Citation:
Fabrication of Robust Superhydrophobic Surfaces onto High-Density Polyethylene Food Contact Surfaces for Enhanced Microbiological Food Safety,
Arcot, Yashwanth; Liu, Shuhao; Ulugun, Beril.; DeFlorio, William; Bae, Michael; Salazar, Karla Solis; Taylor, Thomas; Castillo, Alejandro; Scholar, Ethan A.; Cisneros-Zevallos, Luis; Akbulut, Mustafa; ACS Food Science and Technology
- Type:
Journal Articles
Status:
Published
Year Published:
2021
Citation:
ÿ¢ÿ¿ÿ¢ Liu, Shuhao; Ulugun, Beril.; DeFlorio, William; Arcot, Yashwanth; Yegin, Yagmuir; Salazar, Karla Solis; Castillo, Alejandro; Taylor, T. Matthew; Cisneros-Zevallos, Luis; Akbulut, Mustafa, ÿ¢ÿ¿ÿ¿Development of durable and superhydrophobic nanodiamond coating on aluminum surfaces for improved hygiene of food contact surfacesÿ¢ÿ¿ÿ, Journal of Food Engineering (2021).
- Type:
Journal Articles
Status:
Published
Year Published:
2021
Citation:
ÿ¢ÿ¿ÿ¢ Liu, Shuhao; Bae, Michael.; Hao, Li; Oh, Jun Kyun; White, Andrew R.; Min, Younjin; Cisneros-Zevallos, Luis; Akbulut, Mustafa, ÿ¢ÿ¿ÿ¿Bacterial Antifouling Characteristics of Helicene-Graphene Filmsÿ¢ÿ¿ÿ, Nanomaterials (2021
- Type:
Conference Papers and Presentations
Status:
Submitted
Year Published:
2021
Citation:
ÿ¢ÿ¿ÿ¢ DeFlorio, William; Ulugun, Beril; Liu, Shuhao; Arcot, Yashwanth; Akbulut, Mustafa, ÿ¢ÿ¿ÿ¿Superhydrophobic Antifouling Steel and Stainless-Steel Food Contact Surfaces to Minimize Cross Contaminationÿ¢ÿ¿ÿ, IFT 2021 (Virtual Meeting).
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2020
Citation:
Development of Dual Functional Superhydrophobic Coatings with Bacterial Antimicrobial and Anticontact Characteristics ÿ¢ÿ¿ÿ¿ Shuhao Liu, YAGMUR YEGIN, Jun Kyun Oh, Mustafa Akbulut, Texas A&M University, College Station, TX, US
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Progress 04/01/19 to 03/31/20
Outputs
Target Audience:We published an article entitled as "Dual-Functional, Superhydrophobic Coatings with Bacterial Anticontact and Antimicrobial Characteristics" in ACS applied materials and interfaces. To disseminate this article to general public and stakeholders, we prepared a news statement about the implications of this work to the food industry: https://engineering.tamu.edu/news/2020/04/new-dual-action-coating-thwarts-bacteria-from-cross-contaminating-fresh-produce.html This information have appeared in various science and extension new outlets. Various stakeholders have reached to the PI and have zoom meetings about the technology, including Bin Zhong (Mantrose-Haeuser Co., Inc. / NatureSeal, Inc.), Sohail Akhter (UPL),Felipe Ramirez (Fagro Postharvest solutions),Piancastelli Patrizia (TMAT-EP), and Dino Zanetta (Società Industrializzazione Progettazione Automazione). Likewise, this information was disseminated by extension specialists globally: Sam Grubisa ( The summary of news outlets showcasing the research findings can be found from: https://acs.altmetric.com/details/75417330 . https://www.freshplaza.com/article/9210472/new-coating-prevents-bacterial-cross-contamination-in-fresh-produce/ Due to coronovirus, all of in-person activies and meetings were canceled in this reporting year. Changes/Problems:Due to COVID-19, the research labs were closed in the university over 3 months. IN addition, during these times and even as of now, procuring some components and ingredient has been challening and receival of research supplies has been hindered as well. As such, we anticipate that there will be some delays on our progress on the project. As the university does not allow any large scale gathering, our plan to hold a workshop in Fall 2020 has been replaced with an online conference. What opportunities for training and professional development has the project provided?The project team has recruited two PhD students for the project in 2019: Mr. Shuhao Liu (with Dr. Scholar) and Mr. Michael Bae (with Dr. Cisneros-Zevallos). Another PhD student has recently started (Mr. William DeFlorio with Dr. Scholar) to work on this project starting in January 2020. Additionally, one undergraduate student in the department of biomedical engineering has been included in the project as part of their undergraduate research education: Ms. Beril Ulugun (working with Drs. Scholar and Cisneros-Zevallos). The main educational goal of this project is to train highly multidisciplinary workforce who has experience in materials science, food science, and manufacturing processes. The focus of the training has been to cultivate their problem-solving abilities, independent thought, and those attitudes essential for conducting research. To this end, the results from their research efforts have been organized and submitted for publication in peer-reviewed journals and presented at professional society meetings the Institute of Food Technologists (IFT) and American Institute of Chemical Engineers (AICHE). Publishing journal articles has helped these researchers to develop skills and expertise in professional writing and experience peer-reviewing process, while presenting at professional meetings has helped them improve their oral communication skills. In addition, the PI has been holding biweekly project meetings in which both researchers have presented their research progress via powerpoint format and discuss their current challenges, if any, and future goals in the context of the overall objectives of the project. These meetings have been important steps for these researchers to go beyond simply reporting the obtained data to explain and assess their data as critically-minded scientists. As part of the technical workforce development, all of the researchers and students have been trained on how to synthesize and functionalize nanoparticle building blocks of coating. In addition, to confirm that the synthesis and functionalization is properly carried out, they have been instructed on some chemical and size characterization techniques, including Fourier-transform infrared spectroscopy and dynamic light scattering. After the preparation of the building blocks, coatings can be prepared on metal and plastic surfaces using different methods. To this end, the researchers have received training on solution deposition, infusion, chemical conjugation, and sintering processes which affixes the coating materials on the food contact surface of interests. Finally, checking quality and morphology of the coatingis the next step in the development phase. In this context, the project senior personnel have training their students and researcher on contact angle measurements, scratch testing, atomic force microscopy, and food microbiology. The training for advance instruments was provided by the staff located in the central facilities such microscopy and imaging center (MIC) and material characterization facility (MCF) at Texas A&M University. As researchers have been involved in microbiological evaluation of these surfaces, they were asked to take biosafety training to ensure that all pathogens are properly handled and potential health risks are minimized. Furthermore, the detailed training on good-practices on microbiological was given to them at the Animal Science Microbiology Center. How have the results been disseminated to communities of interest?So far, four modes of transfer have been used to disseminated the critical findings and results of the project to communities of interests. First, publications on the peer-reviewed journals have been used as a main means of disseminating the project findings. We selected journals that have relatively high-impact factors and also broad reach. These journals were ACS applied materials and interfaces and food control. Second, oral and poster presentations have been given at major annual conferences related to the project topic: IFT and AICHE. Third, a news article was prepared to summarize the reach findings at a more basic level to reach out to the general public and stakeholders: https://engineering.tamu.edu/news/2020/04/new-dual-action-coating-thwarts-bacteria-from-cross-contaminating-fresh-produce.html Four, an undergraduate student has been involved on this project. The advance knowledge associated with this project has been transferred to her, with a goal of increasing her instrest in future careers in engineering and technology. What do you plan to do during the next reporting period to accomplish the goals?Up to now, we have focused on the permanent modification of new food contact surfaces that are used in food processing and grading machinery during their production stage. Our current efforts have mostly involved aluminum surfaces so far. We plan to extend our studies by finding appropriate chemistries for stainless steel and plastic surfaces in the next reporting perior. In addition, our focus next year will also be on the development of sprayable formulation that can be applied on existing components of food machinery and equipment. Furthermore, we will also investigate the microbiological performance of these coatings on different contamination scenarios commonly occurring in food industry settings. Finally, the water efficiency of these coatings will be investigated using hydrology assays that we have developed. Finally, we plan to hold an advisory board meeting to get more guidance from stakeholder meeting in the next reporting year. This activity will be led by our extension specialist, Dr. Masabni, in collaboration with the project PI. Our original plan was to have a workshop at the College Station. However, due to COVID-19, we consider organizing an online workshop via ZOOM or TEAMS interface.
Impacts
What was accomplished under these goals?
Despite advances in hygiene, consumer knowledge, and food washing and sanitizing technologies; foodborne illnesses still represent significant health and financial burdens in the US. According to the Centers for Disease Control and Prevention (CDC) survey data, about 9.6 million Americans per year suffer from domestically acquired foodborne illness associated with 31 identified pathogens. While 56,000 of these incidences led to hospitalizations, 1,300 cases resulted in deaths. A recent study reported that foodborne illnesses are responsible for an annual burden to society of approximately $36 billion, with an average identified illness estimated to reduce quality-adjusted life days by 0.84, which is monetized and included in the average cost of burden per illness at $3,630 . A major fraction of the foodborne outbreaks are associated with fresh vegetables partly because they are often consumed without a cooking step that can inactivate pathogens on them. Fresh vegetables can become contaminated with human pathogens at multiple points along the farm-to-table production/supply chain. Potential sources of pathogen contamination in pre-harvest include soil, wildlife feces, soil amendments, agricultural water, dust, wild or domestic animals, and field workers. Then, at the post-harvesting stage, handling operations such as washing/sanitizing, cutting, and packaging/storing provide numerous opportunities for cross-contamination. Postharvest operations have been identified as the stage where most of the mechanisms resulting in pathogen transfer or increase occurs . Equipment and machinery used for sorting, processing, and packing can contribute to the cross-contamination/recontamination of vegetables by pathogens and compromise their microbiological safety, thereby increasing risk of foodborne illness for consumers. The project being proposed here is precisely aimed at tackling this issue by developing smart surfaces with inherent resistance and repellency against bacterial pathogens for equipment and machinery surfaces coming in contact with vegetables. In the long-run, industry can use these strategies to reduce outbreak risks and improve food safety, hygiene, and consumer confidence. All equipment and machinery surfaces used for sorting and processing need to be frequently washed, cleaned, and sanitized, representing a large portion of total water used by food industry. Being water a non-renewable resource, water conservation is paramount. In addition, potential water availability limitations can result in rising costs and prices of water. Therefore, changes in public preferences regarding water allocation among competing uses, increasing budget scrutiny in the national and state legislatures, and increasing awareness of climate; there is a growing need to improve water-use efficiency. Because of the self-cleaning nature of surfaces and coatings being developed in this project, contact surfaces will require a smaller amount of water use for cleaning and sanitization. As such, this work also addresses a major economic, environmental, and social need of sustainability. So far, as an accomplishment, we have developed three different novel coatings that can address the abovementioned needs of food industry and food machinery components. First, we developed a dual-functional coating for aluminum surfaces that relies on the controlled immobilization of lysozyme enzyme (muramidase) into interstitial spaces of pre-sintered, nanostructured thin film based on ~200 nm silica nanoparticles and the sequential chemisorption of an organoflurosilane to the available interfacial areas (Figure 1). The mean diameter of the resultant lysozyme microdomains was 3.1±2.5 µm with an average spacing of 8.01±6.8 µm, leading to a surface coverage of 15.32%. The coating had an overall root mean square (rms) roughness of 539±137 nm and roughness factor of 1.50±0.1, and demonstrated a static, advancing, and receding water contact angle of 159.0±1.0°, 155.4±0.6°; and 154.4±0.6°, respectively. Compared to the planar aluminum, the coated surfaces produced a 6.5±0.1 (>99.99997%) and 4.0±0.1 (>99.99%) log-cycle reductions in bacterial surfaces colonization against Gram-negative Salmonella Typhimurium LT2 and Gram-positive Listeria innocua, respectively. We anticipate that the implementation of such a coating strategy on food-contact surfaces can significantly reduce or eliminate potential risks associated with various contamination and cross-contamination scenarios. https://tamucs-my.sharepoint.com/:i:/g/personal/makbulut_tamu_edu/EXOFiKmgmqdNrHK1iMvloZIB4wcV98utgDP3Vzrw1ToAYQ?e=4KGc50 Figure 1. The illustration of dual functional coating with antiadhesion and antimicrobial properties Second, another class of coating was developed based on helicene chemistry. To optimize their performance, interfacially-assembled [7]helicene films were deposited on monolayer graphene using Langmuir-Blodgett trough at varying surface pressures by utilizing the interactions of nonplanar (helicene) and planar (graphene) π-π interactions. The molecular packing and the areal density of helicene domains on graphene could be well-controlled with the lateral surface pressure: An increasing surface pressure resulted in more compact and denser helicene domains. With a full coverage of helicene, the contact angle of water on bare graphene increased from ~82° to ~107°. Most intriguingly, we found that bacterial adhesion of Staphylococcus aureus on graphene with helicene film was noticeably lower than that on bare graphene, corresponding to up to 96.8% reductions in bacterial adhesion. https://tamucs-my.sharepoint.com/:i:/g/personal/makbulut_tamu_edu/EbsY6rqapDBGuE4zQriAdJUBz_qenrln4Rs8zwRB4tIHxg?e=c2ICaW Figure 2. SEM micrographs indicating bacterial antiadhesion properties of helicene based coatings that can be implemented on stational food contact surfaces. Third, we also developed a durable superhydrophobic coating on aluminum surfaces fabricated by sequential deposition of ultrahard nanodiamond, self-assembly of l-3,4-dihydroxyphenylalanine (l-dopamine, L-dopa), and chemical modification with an organoflurosilane. This coating achieved static, advancing, and receding water contact angles of 159.0±2.5°,154.0±2.4°; and 153.7±1.7°, respectively. A water sliding angle of 23.9±3.8° was also achieved, representing water super-repellency with a low overall root mean square (rms) roughness of 173.5±69.6 nm. This could be regard as "hygienic" in food engineering applications. In comparison to the bare, unmodified aluminum, the coated aluminum surfaces prevented the attachment of 99.5% of applied Escherichia coli O157:H7 (E.coli O157:H7) and 99.0% of Staphylococcus aureus (S. aureus) cells. In addition, the coated surfaces demonstrated a high mechanical resistance during durability tests conducted by scratching the surfaces with nylon ball for 10,000 cycles. Overall, we anticipate that implementation of this coating could improve safety and hygiene of food contact surfaces used by food industry, significantly reducing the potential risk of cross contamination. https://tamucs-my.sharepoint.com/:i:/g/personal/makbulut_tamu_edu/EewiSOHzsl5Go6Ww9MllRUsBu55vfruGFyOnD0FzAt4O6Q?e=kGenQI Figure 3. The illustration of ultradurable superhydrophobic coating relying on nanodiamond
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Liu, Shuhao, Jeremy Zheng, Li Hao, Yagmur Yegin, Michael Bae, Beril Ulugun, Thomas Matthew Taylor et al. "Dual-Functional, Superhydrophobic Coatings with Bacterial Anticontact and Antimicrobial Characteristics." ACS Applied Materials & Interfaces (2020).
- Type:
Journal Articles
Status:
Under Review
Year Published:
2020
Citation:
Shuhao Liu, Michael Bae, Li Hao, Jun Kyun Oh, Luis Cisneros-Zevallos, Mustafa Akbulut, "Bacterial Antifouling Characteristics of Helicene-Graphene Films", Materials Letter
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2020
Citation:
Shuhao Liu, Yashwanth Arcot, William Deflorio, Thomas Taylor, Luis Cisneros-Zevallos, Mustafa Akbulut; Durable Superhydrophobic Coatings on Polymer Surfaces With Bacterial Anti-Adhesion Characteristics, IFT 2020 (Virtual Meeting)
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2020
Citation:
Shuhao Liu, Beril Ulugun, William Deflorio, Thomas Taylor, Luis Cisneros-Zevallos, Mustafa Akbulut; Development of Bacterial Anti-Adhesive and Antifouling Coatings for Metal Surfaces to Enhance Food Safety and Hygiene, IFT 2020 (Virtual Conference)
- Type:
Journal Articles
Status:
Submitted
Year Published:
2020
Citation:
Shuhao Liu, Beril Ulugunb, William DeFlorio, Yashwanth Arcot, Yagmur Yegin, Karla Solis Salazar, Alejandro Castillo, T. Matthew Taylor , Luis Cisneros-Zevallos, Mustafa Akbulut "Development of durable and superhydrophobic nanodiamond coating on aluminum surfaces for improved hygiene of food contact surfaces"
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